Electromagnetic power-transmitting apparatus.



v A. H. NEULAND. ELECTROMAGNETIC POWER TRANSMITTING APPARATUS.

APPLICATION FILED AUG.8| i914.

Patented Mar. 25, 1919.

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ELECTROMAGNEUC-POWER TRANSMITTING APPARATUS.

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ALFONS H. NEULAND, OF SAN FRANCISCO, CALIFORNIA.

ELECTROMAGNETIC POWER-TRANSMITTING APPARATUS.

Specification of Letters Patent.

Patented Mar. 25, 1919.

Application filed August 8, 1914. Serial No. 855,873.

To all whom it may concern:

Be it known that I, ALroNs H. NEULANn, a subject of the Czar of Russia,and a resident of the city and county of San Francisco, State ofCalifornia, have invented certain new and useful Improvements inElectroina netic Power-Transmitting Apparatus, of which the following isa specification.

The invention relates to power transmitting apparatus and particularlyto such apparatus of the electromagnetic type, whlch is adapted totransmit power from one rotatable element to another, as from one shaftto another.

An object of my invention is to provide a power transmitting apparatusin which the driven member may rotate at a different angular velocitythan the driving member and in which the speed of the drivenmember maybe varied with relation to the speed of the driving member. The speed ofthe driving member may be maintained constant at the most efficientspeed of the prime mover and the speed of the driven element may bevaried from zero to synchronism with the driving element or above thespeed of the driving element. and this may be accomplished without thedissipation of energy in external resistances and the like.

Another object of the invention is to provide a power transmittingapparatus in which not only the speed of the driven element may bevaried with relation to the speed of the driving element, but in whichthe direction of rotation of the driven element may be reversed withrelation to the direction of rotation of the driving element, and thismay also be accomplished simply and without the external dissipation ofenergy.

Another object of the invention is to provide a power transmittingapparatus in which the driven element is rotatable at an adjustablefixed speed at all loads for a constant speed of the driving element,that is, the speed of the driven member may be adjusted to any angularvelocity, and such velocity will remain constant independent ofvariations of the load.

The invention possesses other advantageous features, some of which, withthe foregoing, will be set forth at length in the following descriptionwhere I shall outline in full that form of the invention which Ihaveselected for illustration inthe drawings accompanying and forming partof the present specification. In the drawings I have shown only onespecific form of my generic invention, but it is to be understood that Ido not limit myself to such form because my invention may be embodied ina multiplicity of forms, each being a species of my said invention. Itis also to be understood that by the claims succeeding the descriptionof my invention, I desire to cover the invention in whatever form it maybe embodied.

Generally speaking, my invention consists in one of its phases, inproducing a torque between an armature and a field element and allowingthe torque to move the field element either in the same or in theopposite direction to the armature. The armature is connected to thedriving shaft, and the field element is connected to the other shaft.

The torque and slip in one form of the present apparatus are dependenton the strength of the field, the current in the armature and the powerfactor of the armature current, and a variation in the torque and slipis obtained by either varying the field current, or by varying theresistances of the armature circuit, or by both.

The field flux in the field element is produced by the magnetizing coil,which may in some cases surround the field element, and in other casesmay be arranged otherwise adjacent the field element. With the armaturerotating and the armature circuits closed through a variable resistanceor short circuited, a torque is produced between the field element andthe armature by reason of their inductive relation. In order to producea high starting torque a sufficient external resistance must be insertedin the armature circuit to consume the entire energy generated therein.This causes the efiiciency of the machine at start and at low speeds tobe low. A much higher efiiciencv and a greater starting torque isobtained by introducing the armature current, which would otherwise beconsumed in the external resistances, into a winding arranged on thestator, and for this purpose the armature has been provided with acommutator and brushes. The leads from the stator winding are soconnected to the brushes that the direct currents collected at thebrushes when the field element is stationary will traverse the statorwindings in such a way, that a flux will be produced which produces abrushes.

late through the windings of the stator and and the neutral point on thecommutator rotates at the same angular velocity as the field andproduces polyphase currents at the These polyphase currents circucreatea revolving field, the angular velocity of which equals the angularvelocity of the field due to the rotation of the driven or fieldelement, and these two fields have quadrature relation at standstill ofthe driven or field element and retain this relation at all speeds ofsaid element. Further, the generated potential in the constant speedarmature is highest when the field is stationary, and as the drivenelement begins to rotate, allowing the field to follow, the armaturepotential is proportionately decreased. Furthermore, a counterelectrometive force is generated in the stator winding, due to theprogression of the flux in the stator which opposes the armaturepotential and again lowers the resultant potential, thus limiting thecurrent in the windings until a point in the speed is reached where thecounter E. M. F. due to the stator windings equals that generated in thearmature. When the turns on the armature equal the turns on the statorthis point is reached at a slip of substantially fifty per cent. Thewinding on the stator is so arranged that portions thereof may be cutout, thereby decreasing the counter E. M. F. and allowing an increase ofcurrent, consequently enabling the speed to increase. In this way anumber of speeds are' obtained above which the speed of the drivenelement cannot rise even though it were free from any load. Anadjustment of the speed, be-

tween the steps obtained by varying the turns of the winding, isobtained by inserting a variable'resistance between the armature andstator windings, and this resistance is employed only when speedsintermediate the steps are desired.

Reversal of direction of rotation of the driven element withoutreversing the direction of rotation of the driving element isaccomplished in several ways. One method consists in having the fieldelement divided into two members, rotatable independent of each otherand so'constructed and arranged that the torque produced between thefield element and the armature current tends to rotate one member in onedirection and the other member in the opposite direction. Another methodof reversal consists in reversing or changing the stator winding withrelation to the commutator brushes, so that a torque in opposition tothat produced by the of the winding.

armature is produced. In the latter method of reversal, notwithstandingthe fact that the torque produced by the armature current is inopposition to the torque produced by the stator winding, the torqueproduced by the stator winding in the opposite direction predominates byreason of the large number of ampere turns therein as compared withthose of the armature. The only energy at start required by the statorwinding to produce this opposing torque is that which is sufficient toovercome the resistance Since the current in the armature to furnishthis energy is comparatively small, the ampere turns are proportionatelysmall, consequently the armature torque is smaller than the torqueproduced by the stator windings, and therefore the torque produced bythe stator windings upon the field element predominates. Where reversalis obtained by the last described means, the field element may consistof a single member.

In the drawings accompanying and forming part of the presentspecification,

Figure 1 is a longitudinal section of one embodiment of my invention.

Fig. 2 is a cross-section of the machine shown in Fig. 1, the armatureand stator windings being shown diagrammatically.

Fig. 3 is a diagrammatic representation of the electric circuits of themachine, including contacts of a controlling device.

Fig. 4 is a continuation of Fig. 3 showing one form of connecting thecircuits at the controlling device, and a diagrammatic representation ofthe resultant connections.

Figs. 5, 6, 7 and 8 are other continuations Fig. 9 is a section of amachine embodying another form of the invention.

Fig. 10 is a cross-section of the machine shown in Fig. 9, the armatureandstator windings being shown diagrammatically.

Fig. 11 is a section of a machine e-mbodving another form of theinvention. I

Fig. 12 is a cross section of the machine shown in Fig. 11, the armatureandst-ator windings being shown diagrammatically.

Fig. 13 is a diagrammatic representation of the electric circuits of themachine shown in Fig. 11.

I shall first describe in detail the construction of the apparatus shownin Figs. 1-8 inclusive, which specific embodiment forms the subject ofdivisional application, Serial No. 166,136, filed May 3, 1917. In thisembodiment of the invention the apparatus comprises a frame or stator 9,on which is arranged the laminated stator element 3, which is annular inshape and which is preterably provided with a plurality of semiclosedslots 4:, for receiving the coils 5 of the stator winding. Arrangedwithin the stator and concentrically disposed with relation thereto isthe laminated armature element 6 which is annular in form and which ismounted on the hub 7 secured tothe shaft 8. The armature element ispreferably provided with a plurality of semi-closed slots 9 in which thecoils 12 of the armature winding are embedded.

Arranged between the stator element and the armature element andconcentric therewith is a field element which in the presentconstruction consists of two members, each comprising two concentricseries 1315 and 1416 of laminated bars, the bars being arranged parallelto the axis of the machine. The alternate series of bars let and 16 aremounted on a spider 17 which is secured to the sleeve or hollow shaft 18ournaled in the bearings 21 and 22 on the frame 2. The series of bars 13and 15 are mounted on a spider 23 which is secured to the shaft 24journaled in a hollow shaft 18. The shaft 24 is formed hollow at itsinner end to provide a bearing for the armature shaft 8.

Means are provided for locking either or both field members againstrotation, or for allowing either member to rotate, as will behereinafter set forth, it being sufficient at this time to state thateither member, that is, bar series 1315 or 1a16, may be locked againstmovement and the other member allowed to rotate.

The hub 7 which carries the armature element 6 extends into acylindrical projection 25 on the frame. Mounted on the cylindricalprojection is the magnetizing coil 96, the magnetic circuit of whichincludes the frame, the projection 25, the hub 7, the armature element6, the field members 13, 14, 15, and 16 and the stator element 3. Thenumber of bars in the various series 13-14L1516 is so proportioned thatthe bars are alined at certain portions and non-alined or staggered atintermediate portions, and the magnetic flux passes principally throughthose portions of the machine at which the bars are alined.

In the present construction each series l315 contains thirty-fiveequally spaced bars, and each series 14:16 contains thirtytwo equallyspaced bars. This arrangement produces three portions of alined barsspaced apart 120 and three intermediate portions of non-alined bars,producing a six-pole machine. The armature is provided with a windingwhich is wound for twice the number of poles as there are alinedportions or for six poles, and the windings are connected to theconnnutaitor 26 which is secured to the shaft 8 in any well-knownmanner.

It is seen that if either of the field members 13-45 or 1416 is rotatedand the other held stationary that the alined portions or poles' rotateat a greater angular velocity than the field member, that is, for therotation of a field member through the angular distance between twosuccessive bars, the alined portion rotates 120 so that the field has amuch higher angular velocity than the field member, and conversely, thefield member has a lower angular velocity than the field. The directionof rotation of the field with respect to the direction of rotation ofthe field member depends upon which field member is rotated. If thefield member 1315 is rotated the direction of rotation of the field isthe same as that of the member, and if field member 1- l16 is rotatedthe direction of rotation is in opposition to that of the member. Thisis caused by the difference in the angular pitch of bars in the seriesof the different members. The relation between the angular velocity ofthe field and the field member is the ratio between the number of barsin one series of the field member to the number of alined portions, thatis, in the present instance, the relation of the angular velocity of thefield I'nember 1315 to the field is as 3 to 35, and the relation of theangular velocity of the field member 1416 to the field is as 3 to 32.

With a current flowing in the magnetizing winding, the armature rotated,and its circuits short circuited or closed through external resistancesa torque reaction is produced between the armature and the fieldmembers, that is, "the field has a tendency to follow the armature. Ifthe inner field .member 1315 is released and allowed to which willresult, in an angular velocity of the field member of threethirty-seconds of the angular velocity of the armature when the fieldreaches synchronism with the armature. The direction of rotation of thefield member 1416 is in opposition to that of the armature, however, forreasons which have hereintofore been set forth. It is evident,therefore, that if the field member 13 -15 is connected to a drivenshaft and the field member 1 t16 held stationary that such driven shaftwill be rotated in the same direction as the armature, but at a lowerspeed, and if the field member 14l16 is connected to the driven shaftand the field member 1315 held stationary, that the driven shaft willrotate in the opposite direction from the armature and at a lower speed.

The armature is provided with a series winding and is wound for twice asmany poles as there are alined portions in the field element, and meansare provided for varying the resistance of the armature circuits so thata varying relation between the speed of the armature and the drivenshaft may be obtained. This may be accomplished by arranging slip ringson the shaft 8 and inserting a variable resistance in the externalcircuit between the brushes which contact with the slip rings, as shownin Fig. 1. For reasons which will hereafter become evident in thedescription of the complete embodiment of the invention, a commutator 26will usually be used instead of the slip rings, but when the statorwindings are not employed, the slip rings may be used instead of thecommutator. By varying the resistance of the armature circuits the speedof the field member may be varied from near synchronism to zero and tonear synchronism in the opposite direction withoutvarying the speed ofor stopping the rotation of the armature, and the maximum torque overthe entire range from zero speed to near synchronism is thus maintained.In this construction, in which the stator is not included, instead ofemploying slip rings and short circuiting the armature windings, thearmature maybe provided with asquirrel cage winding.

A construction which excludes the stator windings, contemplates thedissipation of the armature currents in external resistances or shortcircuits, and this construction is applicable to conditions where aparticularly high torque at start and at low speeds is not essential. Amuch higher efiiciency and a greater starting and low speed torque,however, is obtained by introducing the armature current into the statorwindings, which are arranged in such a way that the torque produced bythe current in the stator windings adds itself to the torque resultingfrom the reaction between the field and the armature current. For thepurpose of commutating the currents generated in the armature, so thatthey may be conducted to the stator windings, the commutator 26 isemployed, and the armature coils are connected to the commutator in anyusual manner. Contact ing with the commutator are stationary brushes3132-38, the brushes being so arranged that polyphase currents can becollected from them by rotating the field and holding the armaturestationary. Assuming the brushes belonging to each phase shortcircuitedor closed through a resistance, the magnetizing coil energized and thefield element held stationary, rotation of the armature will inducecurrents in its windings which will appear as direct currents in theresistances connected to those brushes which have a neutral positionwith respect to the field poles. The other brushes closed through theirrespective resistance will also carry a direct current, but of lesserintensity, depending upon the position they occupy on the commutator. Ifthe field element is released and the field allowed to rotate, thisneutral position progresses ata corresponding angular velocity. Thus, asthe neutral position passes the brushes belonging to the various phases,an alternating polyphase current is flowing in the resistancesconnecting them. The brushes are connected to the stator windings,sothat the polyphase currents collected are introduced into the statorwindings. This winding is arranged for as many poles as the winding onthe armature and connected for as many phases as obtain in the currentscollected from the commutator brushes. In the present embodiment, Fig.2, I have shown a three hase stator winding, the coils 5 (in full lines)belonging to one phase; the coils 5 (in dot and dash lines) belonging tothe second phase; and the coils 5 (in dotted lines) belonging to thethird phase. The leads ll424=3 44-45-46i784:9505152 are so connected tothe brushes 31-3233 that the currents collected will traverse the statorwindings in such a way that the flux produced thereby produces a torquewhich adds itself to the torque resulting from the reaction between thefield and the armature cur rent. The polyphase currents collected at thebrushes circulate through the stator windings and create a revolvingfield having the same angular velocity as the field member. The fieldsof the stator and armature have quadrature relation at standstill of thefield member and retain this relation at all speeds of the field memberand maintain a torque as long as the armature E. M. F. predominates overthe stator E. M. F. The direction of rotation of the driven shaft isdependent as has been heretofore ex-- plained, upon which field member1315 or 1416 is connected to the driven shaft.

I have stated hereinbefore that the speed of rotation of the fieldmember with relation to the speed of rotation of the armature may bevaried by varying the arrangement of the stator windings. This may beaccomplished by arranging a controlling device in the circuits betweenthe brushes and the stator windings, and this controlling device I havediagrammatically illustrated in Figs. 4 to 8 inclusive. The leads L1 to52 inclusive, of the stator windings, terminate at contacts A of thecontrolling device and the circuits from these leads to the brushes313233 are completed through either of the contacts BC DEF of thecontrolling device, which contacts are connected in diiferent ways, sothat the circuits of the stator windings may be varied. In Figs. 4 to 8inclu sive, I have shown five different steps or arrangements ofcontacts in the controlling apparatus, together with diagramsillustrating the connections effected by the different steps. Differentsteps in speed are obtained by varying the number of turns in series inthe stator winding. The winding of each phase in the illustrated form isdivided into two parts and to obtain the largest number of turns inseries across the brushes, both parts of each hase are connected inseries, and the windings of the three phases are connected in starfashion as shown in Fig. 4. This method of connection produces the lowerspeed of the driven element.

The second step in the speed variation is shown in Fig. 5, in whichthere is a fewer number of turns in series across the brushes. This isproduced by connecting the three phases in delta, leaving the two partsof each phase still in series. The third step, with a still fewer numberof turns in series, is shown in Fig. 6, in which the two arts of eachhase are connected in multiple and the resultant windings of the threephases in star fashion. The fourth step, with a still fewer numberofturns in series is shown in Fig. 7, in which the multiple windings ofthe three phases are connected in delta fashion. The fifth step, ormaximum speed and low torque step, is shown in Fig. 8, in which all ofthe stator windings are open circuited and the brush leads closed. Thelower speed is obtained with the form of connection shown in Fig. 1 andthe speed is increased as the connections shown in Figs. 5 to 8inclusive are made, the speed of the driven element when the connectionsof Fig. 8 are employed being near synchronism, or in the presentembodiment near either three thirty-fifths, or three thirty-seconds ofthe speed of the armature, depending on the relative direction ofrotation of the driven element and the armature.

In order to obtainvariations of the speed, between the speed stepsobtained by varying the stator winding connections, variable resistances545556 are included between the brush leads and the stator winding, andby increasing the variable resistance the speed is lowered and viceversa.

Speed regulation of the driven or field element may be obtained by othersuitable means for changing the relative armature and stator potential,such as a transformer or auto-transformer, in which case the winding onthe stator need not be changed. The application of this method in itsvarious forms will suggest itself to those familiar with the art andrequires no detailed description herein.

I have stated hereinbefore that either or both field members 1315 and1116 may" shaft 57 and the other member held stationary. The fieldmember 13-15 is provided with a flange 58 which is preferably secured tothe series of bars 13. The inner face of the flange 58 is inclined, anddisposed in close relation thereto is an annular wedge 59 having aninclined face corresponding to the inclination of the face of theflange. The wedge is movable axially into and out of engagement with theflange 58, and when in engagement, prevents the flange and consequentlythe field member 13-15 from rotating. The wedge 59 is supported on bolts61 which are longitudinally slidable in the frame 2 and which aresecured at their outer ends to the screw threaded ring 62. Engaging thering 62 is a nut 63 which is capable of rotational movement only, beingprovided for that [purpose with suitable means, such as the handle 64.It is seen that as the nut is rotated, the ring 62 and wedge 59 aremoved axially, so that the wedge may be readily moved to lock or releasethe field member 18-45.

Splined to the bearing 22 is a sleeve 65 which is provided on its innerface with a plurality of slots which are adapted to be engaged by teethor projections on the outer face of the clutch member 66 which is .se

cured to the hollow shaft 18 to which the field member 14.16 is secured.The sleeve 65 is movable loiwituclinally by suitable means, such as thelever 67 and when moved into engagement with clutch member 66 locks thefield member 14-16 against rotation.

The shaft 24, to which the field member 1.315 is secured, projectsbeyond the end of the hollow shaft 18 and extends into and supports thedriven shaft 57. Secured to shaft 24 between shafts 18 and 57 is anexternally toothed clutch member 68. Splined to shaft 57 and engagingsleeve 65 is a sleeve member 69 whichis provided on its face with aplurality of slots which are adapted to be engaged by the teeth onclutch members 66 and 68 respectively. The sleeve 69 is rotatableindependent of sleeve 65 but is movable longitudinally therewith. lVhensleeve 65 is moved longitudinally into engagement with clutch member 66,thereby locking field member 1 l16, sleeve 69 is moved into engagementwith clutch member 68, connecting the field member 1315 with the drivenshaft 57. Vhen the sleeve 65 is moved in the opposite direction, sleeve69 is moved into engagement with clutch member 66, connecting the fieldmember 1116 with the driven shaft 57. The field member 13-15 is lockedagainst rotation by the wedge 59. a

The bars in the series 181f1516 are each composed of a bolt 71,preferably square in cross section, upon which the laminations fori ningthe bars are placed.

The bar series 14 is connected to the bar series 16, which is directlysecured to the spider 17, by the annular plate 72. The spiders 17 and 23are preferably curved in cross sect-ion so that the spider hubs mayoccur conveniently within the frame of the machine, thereby producing acompact construction. The spiders and the side of the frame 2 whichcontains the bearing 21 are made of non-magnetic material, such asbrass, so that the magnetic flux will travel in its proper path.

In this machine, since the rotating field has a higher angular velocitythan the field element, in one case thirty-five thirds higher and in theother case thirty-two thirds higher, the maximum angular velocity of thedriven shaft is three thirty-fifths or three thirty-seconds of theangular velocity of the armature, depending upon the direction ofrotation of the driven shaft with respect to the armature. The speed ofthe driven shaft may be varied from Zero to near synchronism in eitherdirection, for a constant speed of rotation of the armature. The torqueof the driven shaft at near synchronism is approxi- I mately eleventimes the torque of the armature shaft. The highest possible torque thatthe driven member is able to develop is maintained over the entire'rangeof speed from zero to near synchronisin in either direction at a veryhigh efficiency on account of the fact that all of the energy isconsumed in the machine and 1s not dlsslpated in external resistances,that is, all of the energy of the driver is transmitted to the drivenelement at all speeds of operation except such portion of the energy asis required to cover the losses in the machine.

\Vhen it is desired to obtain a speed of the driven element in excess ofthe speed of the driving element, that shaft 57 may constitute thedriving shaft and shaft 8 the driven shaft, in which case the speed ofshaft 8 may approach at its maximum thirty-five thirds or thirty-twothirds of the speed of shaft 57, depending upon the direction ofrotation of shaft 8 with respect to shaft 57.

In the construction shown in Figs. 9 and 10 I have provided a. machinein which at synchronism the driven shaft rotates at the same angularvelocity as the driving shaft. In this construction the field has thesame angular velocity as the field element, in contradistinction to theconstruction heretofore described in which the field has a differentangular velocity than the field element. In the construction shown inFigs. 9 and 10 it may be stated that the field element is the field. Thearmature and stat-or in this construction are wound in the same manneras different angular velocities of the driven shaftwith respect to thedrive shaft.

The field member comprises a plurality of pole pieces 75, and thewindings are arranged to conform to the number of pole pieces employed,in the present instance there being six poles and six pole windings.Each pole piece 75 is surrounded by a field or magnetizing winding 76,the windings being arranged to produce the proper polarity. The windingsare energized from a source of direct current 76 which is connected bybrushes to slip rings in the rotative spider 77 of the field member,with which slip rings the field windings 76 are connected, as shown inFig. 9. The pole pieces 7 5 are arranged intermediate of the concentricarmature and stator and are secured to the spider or disk 77 which issecured to the shaft 78. Since the field rotates at the same angularvelocity as the field member, the speed of the field member may bevaried from zero to near synchronism with the speed-of the armature.Reversal of direction of rotation of the driven element is produced byintroducing the current into the stator windings in such a way as tobring about the torque between the stator windings and the field inopposition to that torque which exists between the armature and thefield, as has been heretofore described.

In Figs. 11, 12' and 13 I have shown another form of the invention inwhich the field element consists of a single rotatable member. In thisconstruction I employ an armature 6 which is provided with a multiplewinding. The winding is connected to the commutator 26 by suitable leadsor taps and the commutator brushes are connected to the windings on thestator 3, the windings on the stator being arranged for a three phasecurrent. Thus, the current generated in the armature is conducted intothe stator windings and produces a torque between the stator and thefield element 81. In this construction, the armature 6 is provided witha plurality of evenly spaced teeth or projections 82, between which theturns of the coils 12 are arranged. The stator is also provided with aplurality of evenly spaced teeth or projections 83, between which theturns of the coils 5 are arranged. The number of teeth on. the statordiffers from the number of teeth on the armature as will be hereinafterexplained.

Arranged between the concentric stator and armature is the rotatablefield element 81 which comprises a laminated ring having a plurality ofevenly spaced teeth or projections 84 on one side facing the teeth onthe armature and preferably an equal number of evenly spaced teeth 85 onthe other side facing the teeth 83 on the stator. The number of teeth 8or 85 on the field element differs from the number of teeth on thearmature and from the number of teeth on the stator, so that the teeth828t are alined at one or more portions and more or less staggered atthe intermediate portions, andthe teeth 83- 85 are alined at one or moreportions and more or less staggered at the intermediate portions. In thepresent illustration 1 have employed twenty-four stator teeth 83,twentysix field element teeth 84 and 85 on each side of the fieldelement, and twenty eight armature teeth 82. This arrangement producestwo portions of alinement between teeth 82 and 84 and two portions ofalinement between the teeth 83 and 85. Assuming for the instant that thefield element is held stationary and the armature rotated, disregardingfor the present the stator and stator windings, a current of twenty-sixcycles per revolution of the armature will be generated in the armaturewinding. Since there are twenty-six teeth 8 1 on the field element andtwenty-eight teeth 82 on the armature there is produced two alined toothportions and two intermediate non-alined tooth portions between thearmature and the field element, the two alined portions being 180 apart.The teeth on the armature and field element are progressively more andmore non-alined between the alined portions and the portions at rightangles thereto, at which latter portions they are in complete staggeredrelation. It will be seen that upon. rotation of the armature a distanceequal to one tooth pitch on the armature, the alined portion isgradually shifted around the circumference of the rotor for an angulardistance of 180, thereby causing the movement of the path of leastmagnetic reluctance for one-half a complete revolution for every angularmovement of the armature for one tooth pitch, or in other words, themagnetic path between the field element and armature makes one completerevolution for each movement of the armature through twice a toothpitch. Since the number of teeth on the armature is greater than thenumber on the field element, the ro tation of the flux path is in thesame direction as that of the armature. Thus, the rotation of thearmature produces a revolving magnetic field. Each revolution of themagnetic field induces two complete cycles in the armature windings, andsince the field travels in the same direction as the armature thewindings on the armature, since they follow the progression of thefield, are cut by the revolving field only twenty-six times for eachrevolution of the armature, instead of twenty-eight times; or inv otherwords, there are twenty-six cycles of current induced in the windingsfor each revolution of the ar mature. The number of cycles perrevolution of generated current in the windings is equal to the numberof teeth on the armature minus the number of alined portions in whichthe field rotates in the same direction as the armature, or in otherwords, the number of cycles per revolution is equal to the number ofteeth on the field element or the member which carries no winding. Thearmature is wound for as many poles as there are alined and nonalinedportions. In the present instance there are two alined and twonon-alined portions, and hence the armature has a four pole winding.

The commutating mechanism of this machine is substantially that patentedin my prior Patent No. 1,17 8,455, and is illustrated diagrammaticallyin Fig. 13. Connected to the armature winding is the commutator 26, anda direct current will be collected at those brushes .Iwhich occupy aneutral position on the commutator with respect to the field. There aretwentysiX coils in the armature winding and twenty-six segments on thecommutator. When a direct current is to be collected the number ofbrushes which are employed in order to cause the point of contact orcommutation to travel in the smile direction as the field or the alinedportions and at the same angular velocity must be less than the numberof segments on the commutator, and the difference in number isdetermined by the number of alined portions. In the present instance,therefore, twenty-four brushes per lead should be employed, the angulardistance between the adjacent brushes being 15. This arrangement,however, would involve a large number of brushes, and the number ofbrushes may be decreased by omitting every second and third brush inevery group of three brushes as illustrated in Fig. 13, producing aspacing of the brushes belonging to the same sign of 15, which willbring about substantially the same progression of the point of contact.

This arrangement I have adopted and the brushes 86 are spaced apart 15,and connected to a common lead.

Therefore, as long as the field member is stationary the current at thebrushes and in the stator windings will be direct. As soon as the fieldelement begins to follow the armature, the current at the brushesbecomes alternating, and the frequency thereof equals 26 cycles for eachrevolution of the field element. This alternating current causes thepoles due to the current in the stator winding to rotate at a velocitywhich will at all times retain quadrature relation with respect to theflux of the field element.

Vith the field element rotating, causing a revolving field in thestator, a counter E.

F. is induced in the stator windings, and since there are twenty-sixteeth 85 on the field element and twenty-four teeth 83 on the statorelement, the current induced in the stator windings will have twentysixcycles per revolution of the field element, as has been heretoforedescribed in connection with the armature currents, that is, the numberof cycles per revolution generated is equal to the number of teeth onthe element which carries no winding.

Since the counter E. M. F. generated in the stator windings has the samefrequency as the current generated in the armature windings, thearmature current is introduced into the stator windings, where it exertsa torque between the stator and the field element which adds itself tothe torque produced between the armature and the field element.

Then the field element begins to rotate due to the torque exertedthereon by the armature current, the field and the field ele ment followthe armature, thereby decreasing the generated armature potentialproportionately. The moving field causes the current at the brushes tobecome alternating and causes a progression of the flux with respect tothe stator windings, inducing a potential therein which opposes the E.M. F. of the armature. "With a given number of turns in series on thearmature and on the stator, a certain speed of the field element willbring about a balance between the two opposing potentials, that is, thepotential generated in the armature which is introduced into the statorwindings and the counter potential generated in the stator windings, andthereby limit the current in the windings. By varying the number ofturns in series of the stator winding, a number of steps in the speed ofthe field element may be obtained above which the speed may not rise.

Due to the fact that the field element consists of a ring having teethon opposite sides, the same flux is enabled to traverse the armature andstator windings, by passing through the ring from an point at which theteeth on one side are almed to any point at which the teeth on the otherslde are alined.

The stator is wound for four poles and connected for a three phasecurrent, and the brushes on the commutator have a spacing adapted tocollect three phase currents when the field element rotates. The numberof brushes in this example, as has been pointed out and as shown in Fig.13, is only one-third of the full number, and therefore the brushes 87of one phase are spaced 10 from the brushes 86 on one side and thebrushes 88 of another phase are spaced 10 from the brushes 86 on theother side, thusfulfilling the requirements of three phase spacing. The

brushes 86 are connected to ring 91, the brushes 87 to ring 93 and thebrushes 88 are connected to ring 92. The rings 919293 are connected tothe three phases of the stator winding 94: in such manner that thenumber of turns of the stator winding may be varied, as for example bythe controller heretofore described, so that the speed of the fieldelement may be varied. Reversal of direction of rotation of the fieldelement, which is secured to the driven shafts, may be effected byreversing one phase of the stator winding, that is, by reversing two ofthe leads from the brushes to the stator windings, and for accomplishingthis result I have shown a reversing switch 95.

I claim:

1. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a stator provided with a winding which isconnected to the armature winding by means of stationary brushes, and arotatable field element in inductive relation to said armature andstator.

2. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a stator provided with a winding, meanscomprising a commutator and stationary brushes connecting said windingsto allow the current generated in the armature winding to flow into thestator winding, a rotatable field element in inductive relation to saidarmature and stator, and means for producing a common magnetic fluxtraversing said armature, field element and stator.

8. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a concentric stator provided with a windingwhich is connected to the armature windingthrough a commutator andstationary brushes, a rotatable field element arranged concentricallybetween said armature and stator, and means for producing a commonmagnetic fiuX traversing said armature, field element and stator.

1. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a stator provided with a winding which isconnected to the armature winding by means of a commutator andstationary brushes, and a field element adapted to rotate in eitherdirection with relation to the direction of rotation of the armaturearranged in inductive relation to said armature and stator.

5. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a stator provided with a winding which isconnected to the armature winding by means of a commutator andstationary brushes, a rotatable field element in inductive relation tosaid armature and stator, and means for varying the speed of saidelement independently of the speed of the armature.

6. In a power transmitting apparatus of the inductor type, an armatureprovided with a winding, a stator provided with a winding which isconnected to the armature winding by means of a commutator andstationary brushes, a rotatable field elementin inductive relation tosaid armature and stator, and means for reversing the direction ofrotation of the field element with relation to the direction of rotationof the armature.

'7. In a power transmitting apparatus of the induction type, a rotatablecurrent generating element, a stationary current consuming element toconsume the current generated in the rotatable element. a rotatablefield element. in inductive relation to said generating and consumingelements, and means including stationary brushes for varying thefrequency of the current supplied to the consuming element.

8. In a power transmitting apparatus of the induction type, a rotatablecurrent generating element, a stationary element arranged to consume thecurrent generated in said rotatable element, means for transferringcurrent between said elements comprising a commutator and stationarybrushes, a rotatable field-element in inductive relation to saidgenerating and consuming eleinents, and means for varying the counterelectromotive force in said consuming element whereby the speed of .thefield element is varied 9. In a power transmitting apparatus of theinduction type, a rotatable current generating element, a stationaryelement including a winding arranged to consume the current generatedinsaid rotatable element, means for transferring current between saidelements comprising a commutator and stationary brushes, a rotatablefield element in inductive relation to said generating and consumingelements, andmeans for changing the relation of the current in saidconsuming element with respect to the field element comprising aswitching mechanism for changing the relation between said stationarybrushes and said winding whereby the'direction of rotation of the fieldelement is reversed.

10. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a stator provided with a winding which is conneted to the armature winding. a rotatable field element in inductiverelation to said armature and stator, means for reversing the directionof rotation of the field element with relation to the di rection ofrotation of the armature. and means for varying the angular velocity ofthe field ,element with relation to the angular velocity of thearmature.

11. In a power transmitting apparatus of the induction type, a rotatablecurrent generating element, a stationary current consuming element,means comprising a commutator and stationary brushes for transferringcurrent between said elements. a rotatable field element arranged ininductive relation to said generating and consuming elements, andmeansfor producing a common magnetic flux traversing said generatingconsuming and field elements.

12. In a. power transmitting apparatus of the induction type, anarmature provided with a winding. a stator provided with a winding whichis connected to the armature winding by means of a commutator andstationary polyphase brushes, a rotatable field element in inductiverelation to said armature and stator, means for producing a commonmagnetic flux traversing said armature, field element and stator, andmeans for varying the number of turns in series in the stator winding.

13. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a stator provided with a polyphase windingwhich is connected to the armature winding by means or" a comn'iutatorand stationary 'polyphase brushes sup plying said stator with polyphasecurrents, whereby a rotating field is produced in the stator, arotatable field element in inductive relation to said armature androtating in electrical synchronism with said stator field, meansforproducing a common magnetic flux transversing said armature, field element and stator means, and. means for re versing the direction ofrotation of the stator field whereby thedirection of rotation of thefield element is reversed. a

141:. In a power transmitting apparatus 0 the induction type, anarmature provided with a winding, a commutator connected to saidwinding, stationary brushes engaging said commutator, a'stator providedwith a winding, conductors connecting the brushes with the statorwinding, a rotatable field element in"inductive relation to said statorand armature, and means for producing a commonniagnetic flux traversingsaid armature, field element and stator.

i 15. In a power transmitting apparatus of the induction type, anarmature with a winding, a commutator connected to said winding,stationary brushes engaging said commutator, a stator provided with awinding, conductors connecting the brushes with the stator winding, arotatable field element in inductive relation to said armature andstator, and means for producing a common magnetic flux traversing saidarmature, field element and stator, the current at the brushes beingdirect when the field element is stationary and alternating when thefield element rotates.

16. In a power transmitting apparatus of the induction type, an armatureProvided with a winding, a commutator connected to said winding,stationary brushes engaging said commutator, a stator provided with awinding, conductors connecting the brushes with the stator winding, arotatable field element in inductive relation to said armature andstator, and means for varying thenumber of turns in series in the statorwinding.

17. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a commutator connected to said winding,stationary brushes engaging the commutator, a stator-provided with awinding, conductors connecting the brushes with the stator winding, arotatable field element in inductive relation to said armature andstator, means for producing a common magnetic flux traversing thearmature, field element and stator, and means for varying the speed ofthe field element with relation to the speed of the armature.

18. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a commutator connected to said Winding,stationary brushes engaging the commutator, a stator provided with awinding, conductors connecting the brushes with the stator winding, arotatable field element in inductive relation to said armature andstator, means for producing a common magnetic flux traversing saidarmature, field element and stator, and means for adjusting the voltagerelation between the armature and stator whereby a plurality ofdifferent ;substantially constant speeds of rotation of the fieldelement are produced for a constant speed of the armature.

19. In a power transmitting apparatus of the induction type, an armatureprovided with a winding, a stator provided with a winding which isconnected to the armature winding, a rotatable field element ininductive relation to said armature and stator, means for producing acommon magnetic flux traversing said armature, field element and stator,and means for producing a plurality of diflerent substantially constantspeeds of rotation of the field element at varying loads for a constantspeed of the armature.

20. In a power transmitting apparatus of the inductor type comprising anouter stationary" member provided with a winding, an intermediaterotatable member, a driven shaft connected to said intermediate member,an inner rotatable member provided with a winding, a driving shaftconnected to said inner member, means for producin a common magneticflux traversing saic three elements, rotation of said inner elementserving to generate a current in the winding thereon, and meanscomprising a commutator and stationary brushes for conducting thecurrent generated to the winding on the outer element.

21. An electrical apparatus of the type having a rotatable armatureincluding a winding and a commutator and stationary brushes wiping thecommutator and a rotatable field member in inductive relation to thearmature, characterized by the fact that the armature is the primarymember and is driven at any predetermined fixed speed by external powerand that the field member is rotatable, whereby, as the speed of thefield member increases from standstill to maximum, the current at thebrushes changes from a zero frequency and maximum voltage to a maximumfrequency and zero voltage,

and a motor element including a winding fed by said variable frequencycurrents.

In testimony whereof, I have hereunto set my hand at San Francisco,California, this 1st day of August, 1914.

ALFON S H. NEULAND. In presence of' H. G. Pnosr,

G. S. DONELIN.

Copies of this patent may be obtained for ave cents each, by addressingthe commissioner of Patents,

' Washington, D. C,"

